In /usr/bin/grub-kbdcomp line 3:
prefix="/usr"
^----^ SC2034: prefix appears unused. Verify use (or export if used externally).


In /usr/bin/grub-kbdcomp line 19:
. "${pkgdatadir}/grub-mkconfig_lib"
  ^-- SC1090: Can't follow non-constant source. Use a directive to specify location.


In /usr/bin/grub-kbdcomp line 21:
self=`basename $0`
     ^-----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
               ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
self=$(basename "$0")


In /usr/bin/grub-kbdcomp line 44:
  echo $1
       ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
  echo "$1"


In /usr/bin/grub-kbdcomp line 61:
	output=`argument $option "$@"`; shift ;;
               ^---------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                         ^-----^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
	output=$(argument "$option" "$@"); shift ;;


In /usr/bin/grub-kbdcomp line 63:
	output=`echo "$option" | sed 's/--output=//'` ;;
               ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	output=$(echo "$option" | sed 's/--output=//') ;;


In /usr/bin/grub-kbdcomp line 76:
ckbcomp $ckbcomp_options | "$grub_mklayout" -o "${output}"
        ^--------------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
ckbcomp "$ckbcomp_options" | "$grub_mklayout" -o "${output}"

For more information:
  https://www.shellcheck.net/wiki/SC1090 -- Can't follow non-constant source....
  https://www.shellcheck.net/wiki/SC2034 -- prefix appears unused. Verify use...
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...